IDEF Partie 1 IDEF. What is IDEF? Definition: IDEF is the common name referring to classes of enterprise modeling languages. Objective: IDEF is used for

IDEF

Partie1 IDEF

What is IDEF?

Definition: IDEF is the common name referring to classes of enterprise modeling languages.

Objective: IDEF is used for modeling activities necessary to support system analysis, design, improvement or integration.

Originally, IDEF was developed to enhance communication among people trying to understand the system. Now, IDEF is being used for documentation, understanding, design, analysis, planning, and Integration.

IDEF History

In the 1970’s, IDEF0 originated in the U.S. Air Force under the Integrated Computer Aided Manufacturing(ICAM) program from a well-established graphical language, the Structured Analysis and Design Technique (SADT).

IDEF Family

IDEF Family of Methods: IDEF0: for Function Modeling (purpose:description) IDEF1: for Information Modeling. (purpose:description) IDEF1x: for Data Modeling. (purpose:design) IDEF3: for Process Modeling. (purpose:description) IDEF4: for Object-Oriented Design. (purpose:design) IDEF5: for Ontology Description Capture.

(purpose:description)

IDEF0- Function Modeling Method

IDEF0 models the decisions, actions, and activities of an organization or system, in order to communicate the functional perspective of a system.

IDEF0 models are created as one of the first tasks of a system development effort because they describe: the functions that are performed, what is needed to perform those functions,

IDEF0 was released as a standard for Function Modeling by the Computer Systems Laboratory of the National Institute of Standards and Technology. (1993)


Syntax: Context Diagram: is a model of the function at the highest

level of inputs, controls, outputs, and mechanisms

Mechanisms

Function Name

Controls

Inputs Outputs

• Inputs: items that trigger the activity• Controls: guide or regulate the activity• Mechanisms: systems, people, equipment used to perform the activity• Outputs: results of performing the activity


Decomposition Diagram: links together the context diagrams

IDEF1- Information Modeling Method

IDEF1 is a method for both analyzing and communicating the structure and semantics of information within a system.

IDEF1 models are used to: Identify what information is currently managed in a real-world

system, both automated system components, and non-automated objects (e.g. people).

Identify the rules for managing the information. Identify deficiencies in the current management of the

information. Specify what information will be managed in a TO-BE

implementation. (TO-BE implementation: Design of the functional architecture)


STRENGTHS IDEF1 requires active participation of the information users,

which serves to accurately model where and how the information is used and managed.

An effective method for documenting the informational requirements of an enterprise, providing a foundation for database design.

IDEF1 enforces a modularity that eliminates the incompleteness, imprecision, inconsistencies, and inaccuracies found in the modeling process.

IDEF1x- Data Modeling Method

IDEF1X is a method for designing relational databases. IDEF1X Model: Graphical and Textual depiction of “What must I

know to do what I do?” IDEF1X is most useful for logical database design after the

information requirements are known and the decision to implement a relational database has been made.

IDEF1X was released as a standard for Data Modeling by the Computer Systems Laboratory of the National Institute of Standards and Technology. (1993)

IDEF1x- Data Modeling Method

STRENGTHS Powerful tool for data modeling. IDEF1X don’t have numerous variants, unlike ER. Depicts the rules governing the management of

information. Used to validate the concepts in the associated IDEF0

model. Helps to discover underlying causes for problems.

WEAKNESSES The modeler must be experienced in order to create good

models. Not suited to serve as an AS-IS analysis tool.

IDEF1 (information Model) vs. IDEF1x (Data Model)

Information Model Data Modelfocuses on:

Information collected, stored, and managed by the organization

Logical relationships within the organization reflected in the information

focuses on: Actual data elements in a

relational database Representation &

structure of the data

used for: Problem identification Requirements definition Information system design

used for: Logical design of

databases & applications Physical design of

database implementation

IDEF1

Partie2 Entity – relation

model

Introduction

Scope

IDEF1 is used to produce a graphical information model which represents the structure and semantics of information within an environment or system.

Introduction

Purpose

IDEF1 is used to model data in a standard, consistent, predictable manner in order to manage it as a resource. The primary objectives of this standard are:1. To provide a means for completely understanding and analyzing an

organization’s data resources;

2. To provide a common means of representing and communicating the complexity of data;

3. To provide a method for presenting an overall view of the data required to run an enterprise;

4. To provide a means for defining an application-independent view of data which can be validated by users and transformed into a physical database design;

5. To provide a method for deriving an integrated data definition from existing data resources.

Introduction

Several appellations Model entity – association Model entity – relationship Model object – relationship

First publication by Dr. Pin-Shan (Peter) Chen (陳品山) 1976

Top down approach: from the discourse universe towards the model

The diagrams created using this approach are called ER diagrams.


Main IDEF1 Concepts Entity: The representation of a set of real or abstract things

(people, objects, places, events, ideas, combination of things, etc.) that are recognized as the same type because they share the same characteristics and can participate in the same relationships.

Entity Instance: One of a set of real or abstract things represented by an entity. The instance of an entity can be specifically identified by the value of the attribute(s) participating in its primary key.


Main IDEF1 Concepts Attribute: A property or characteristic that is common to some

or all of the instances of an entity. An attribute represents the use of a domain in the context of an entity.

Key, Candidate: An attribute, or combination of attributes, of an entity whose values uniquely identify each entity instance.

Key, Composite: A key comprised of two or more attributes. Attribute, Non-key: An attribute that is not the primary or a part

of a composite primary key of an entity. A non-key attribute may be a foreign key or alternate key attribute.


Main IDEF1 Concepts Relationship: An association between two entities or between

instances of the same entity. Relationship Name: A verb or verb phrase which reflects the

meaning of the relationship expressed between the two entities shown on the diagram on which the name appears.

Verb Phrase: A phrase used to name a relationship, which consists of a verb and words which comprise the object of the phrase.

Relationship Cardinality: The number of entity instances that can be associated with each other in a relationship.


Main IDEF1 Concepts Constraint, Cardinality: A limit on the number of entity instances

that can be associated with each other in a relationship. Existence Dependency: A constraint between two related entities

indicating that no instance of one (child entity) can exist without being related to an instance of the other (parent entity). The following relationship types represent existence dependencies: identifying relationships, categorization relationships and mandatory non-identifying relationships.

Functional Dependency: A special kind of integrity constraint that applies within the confines of a single entity “R”, where each “X” value of “R” has associated with it at most one “Y” value of “R” (at any one time). Attributes “X” and “Y” may be composite.

Presentation

ATTRIBUTE

Definition : elementary information, nondeductible from another one, presenting an interest in the considered domain.

a value taken by a property is an occurrence

a property is atomic if it can not be decomposed

Synonyms : Attribute, characteristic, constituent,…

Description : a property can be defined by A name, a label A type A length

All properties must be mentioned on a model.

Take care to avoid: two same names for a property A same name for two properties A property must only appear one time in the model

Presentation

ENTITY, INSTANCE, KEY

ENTITIES

Definition : Representation of tangible or intangible elements important for the system

to describe Entity class correspond to a set of entities whose definition is the same Entity classification inside a class is called classification or instantiation Entity class can be viewed as a set properties that are gathered

Synonyms : Object

Description : A name, a label An identifying characteristic Some properties

label

List of properties

Presentation


INSTANCE

Definition : Each property is valuated by an instance which corresponds to a value define in a (finite or infinite) set of values.

Remark : Each occurrence of an entity class have the same properties.

Ex. Entity class « Student »

2154DurandMarie

2156DurandMarie-Paul

2406MottteJean

All instance have the same properties: number, family name and first name

StudentNumberFamily nameFirst name

Presentation


KEY

Definition : an identifying characteristic is a specific property that allow to

identify one and only one entity. an identifying characteristic is an entity specific property so that

there does not exist two occurrences for which this property could take a same value

Example:

Which property can be used as identifying characteristic for a student ?

its student national university subscription number

Formalism : an identifying characteristic is underlined

StudentNumberFamily nameFirst name

Presentation

RELATIONSHIP, INSTANCE, RELATIONSHIP TYPOLOGY

RELATIONSHIP

Definition : a relationship represents a semantic link between 2 or more entities

that belong to the considered universe. A link is mentioned if there is an interest regarding the universe.

a class of associations contents all associations of a same type a relation must be specific regarding the different entities that are in

relation. a relation can be characterized by specific properties

Synonyms : Association

Description: A name, a label Properties, characteristic identifying

Presentation


RELATIONSHIP

Formalism :

CALL

NumAnnTexteNbLignesDomNbSemDateRédac

CUSTOMER

NumCliNomPrénomRueCPVille

JOURNAL

RubTarifPrem

Concern write

Here a customer can write a call which concerns a journal

Presentation


INSTANCE

Definition : an association instance represents a specific link between two or more entity occurrence.

Description : an association instance is made up of one and only one entity

instance of each entity that are linked. all association instance have the same properties

16Charente

2DURANDPaul

1DUPONTRené

The scheme represents two examples of the

association occurrence « live ».

Presentation


RELATION TYPOLOGY

There is no limit regarding the number of entity class that can be in relation.

it is possible to define “bin”ary relation :

It is possible to definite “n”ary relation

CE3 CE4

Presentation


RELATION TYPOLOGY

Reflexive relation

It expresses the links between entity instance

Ex. In project management a task can be previous another one and can be followed by one or more task.

Task

N° of taskTo be previous than

Presentation


RELATION TYPOLOGY

Multiple relation

Several links can exist between two or more entities

EMPLOYEENumberName

DEPTNoDepartmentName of the department

live

work

Presentation


RELATION TYPOLOGY

Remark: relationship primary key 1 ) Primary key of a relationship is obtained by associating the primary keys of each

entity participating in the relation.

2) Each occurrence of the relationship is concerned by one and only one value of the primary key.

Propriétaire

denomination

MaisonAcheter

Dénomination – jour - nom

Prix d’achat

nom

Date

jour

Presentation

CONSTRAINTS CARDINALITY

Definition : The cardinality of a link between an entity and an association precise the minimum and maximum number of time that an entity instance is concerned by the association

Formalism : Cardinality is noted using two numbers “ m,M ”. “ m ” is the minimal cardinality and “ M ” the maximal cardinality Minimal cardinality: is the minus number of time for which an entity

occurrence can participate to the relation (0 or 1). Maximal cardinality: is the major number of time for which an entity

occurrence can participate to the relation (1 or N).

Presentation


Example : A firm manages products that are stored or not (produced on demand). It has factories that contains at least one product.

A product can not be stored in a factory which means that there can exist one occurrence of a product without any occurrence of storage. 0

A product can be stored, but only in one factory, then one occurrence of product can exist only with one occurrence of storage. 1

A factory stores at the minimum one product. 1 A factory can store more than one product. n

1,nproduct

storefactory

0,1 1,n1,n

Presentation


Remark: couple can be (0,1), (0, N), (1, 1) and (1,n)

Remark: a minimal cardinality of 1 is justified by the fact that all occurrence of the entity need that the association exist.

Remark: the discussion around a minimal cardinality 0 or 1 is interesting only if the the maximal cardinality is 1.

Presentation

Syntactic rules

Entity normalization: all entity that can be replaced by an association must be replaced

Name normalization: the name of an entity, an association or an attribute must be single

Normalization of keys : each entity must have a key (preferably an entirety, incremented automatically)

Normalization of attributes : replace the attributes in several specimens in an additional association of maximum cardinality N and not to add calculable attributes starting from other

Normalization of attributes of associations : attributes of an association must directly depend on the keys of all entities that are associated

Normalization of associations: it is necessary to eliminate phantom associations

Normalization of constraints: the minimal cardinality is always 0 or 1, the maximal cardinality is always 1 or n

Normalization

Normal forms

Normalization

NORMALIZATION RULES

Definition: the process of refining and regrouping attributes in entities according to the normal forms.

Normal Form:

Definition: the condition of an entity relative to satisfaction of a set of normalization theory constraints on its attribution. A specific normal form is achieved by successive reduction of an entity from its existing condition to some more desirable form. The procedure is reversible.

b) Second Normal Form (2NF) - An entity is in 2NF if and only if it is in 1NF and every non-key attribute is fully dependent on the primary key.

c) Third Normal Form (3NF) - An entity is in 3NF if and only if it is in 2NF and every attribute that is not a part of the primary key is non-transitively dependent (mutually independent) on the primary key. Two or more attributes are mutually independent if none of them is functionally dependent on any combination of the others.

Normalization

NORMALIZATION RULES

a) First Normal Form (1NF) - An entity is in 1NF if and only if all underlying simple domains contain single values only.

MatriculeNameFirst NameSexChil first name

EMPLOYEE

NON VALID

A2783DupontAlfredMaleLéo, Léa, Lola

MatriculeNameFirst nameSex

EMPLOYEE CHILDREN

Be parent of O,n 1,1

First name

VALIDE

Normalization

NORMALIZATION RULES

Second Normal Form (2NF) - An entity is in 2NF if and only if it is in 1NF and every non-key attribute is fully dependent on the primary key.

level-SectionAcces ageDate of evaluationRoom number

Class

Normalization

NORMALIZATION RULES

Third Normal Form (3NF) - An entity is in 3NF if and only if it is in 2NF and every attribute that is not a part of the primary key is non-transitively dependent (mutually independent) on the primary key. Two or more attributes are mutually independent if none of them is functionally dependent on any combination of the others

Normalization

Simplifying rule

Existence Dependency: A constraint between two related entities indicating that no instance of one (child entity) can exist without being related to an instance of the other (parent entity). The following relationship types represent existence dependencies: identifying relationships, categorization relationships and mandatory non-identifying relationships.

Functional Dependency: A special kind of integrity constraint that applies within the confines of a single entity “R”, where each “X” value of “R” has associated with it at most one “Y” value of “R” (at any one time). Attributes “X” and “Y” may be composite.

NameFirst nameAdress

Name

Student Classbelong1,1 1,n

MCD elaboration

The steps To draw up a list of the data starting from the documents of the company, and more generally of all the carriers data To classify it these data alphabetically in order to sweep all on the regroupings properties To carry out a priori the purification of the polysemes, the synonyms and the redundancies. To locate the identifiers existing to release the natural objects To attach to these objects the properties in functional dependence of their identifier To place the relations and to attach if need be the functional properties in dependence to them several identifiers To consider the remaining properties in order to gather them into object for which one will create the not formalized identifiers To study the cardinalities of each couple entity-association, Simplifier the model using the constraints of functional integrity, Checking the model using the rules

Documents

IDEF Partie 1 IDEF. What is IDEF? Definition: IDEF is the common name referring to classes of enterprise modeling languages. Objective: IDEF is used for